Satellite data of the 2018 Sierra Negra eruption in the Galápagos islands

The 2018 eruption of Sierra Negra volcano, Galápagos, Ecuador has provided
new insights into the mechanisms of caldera resurgence, subsidence, and
fissuring at basaltic shield volcanoes. Here, we integrate local (~0.4 km)
seismo-acoustic records and regional (~85 km) infrasound array data to
present new observations of the 2018 Sierra Negra eruption with improved
time and spatial resolutions. These observations include: air-to-ground
coupling ~2 hours before the time of the eruption onset, migration of the
infrasound tremor from 22:54 June 26 to 12:31 June 27 UT (all times in
UT), and persistent infrasound detections during the weeks between 5 July
and 18 August from an area that does not coincide with the previously
documented eruptive fissures. We interpret air-to-ground coupling as
infrasound tremor generated in the nearby fissures before the main
eruptive phase started, although ambiguity remains in interpreting a
single seismic-infrasonic sensor pair. The progressive location change of
the infrasound tremor agrees with the migration of the eruption down the
north flank of Sierra Negra at a rate of ~0.15 ± 0.04 m/s. The weeks-long
persistent detections coincide with a region that has thermal anomalies,
co-eruptive deformation, lava fields, and geological features that could
be interpreted as multiple lava tube skylights. Our observations and
interpretations provide constraints on the mechanisms underlying fissure
formation and magma emplacement at Sierra Negra.